Metal carbonate initiator and method for polymerizing isocyanates using the same

a technology of initiators and metal carbonates, which is applied in the direction of organic chemistry, physical/chemical process catalysts, organic compounds/hydrides/coordination complex catalysts, etc., can solve the problems of difficult control of the molecular weight of a polymer and to obtain a monodispersed polymer, the method of controlling the polymerization of isocyanates is a very difficult problem, and the anionic polymerization of isocyanates requires extreme reaction conditions. to achiev

Inactive Publication Date: 2009-11-24
GWANGJU INST OF SCI & TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Benefits of technology

[0018]Accordingly, an object of the present invention is to provide a metal enolate initiator for polymerizing isocyanates and a method for polymerizing isocyanates by anion polymerization using the same that can prevent depolymerizaton and improve reaction time and efficiency without the use of a separate additive.

Problems solved by technology

As a result, it is difficult to control the molecular weight of a polymer and to obtain a monodispersed polymer.
Moreover, the anionic polymerization of isocyanates requires extreme reaction conditions such as high vacuum and low temperature due to a high reactivity of an isocyanate monomer.
A method for controlling the polymerization of isocyanates has been a very difficult problem for numerous researchers, and extensive research aimed at polymerizing isocyanates with a controlled structure by the anionic polymerization has continued to progress.
Although this polymerization offered an improved yield, it was difficult to control the molecular weight and to obtain a monodispersed polymer, and thereby it was impossible to find a condition for living polymerization.
Meanwhile, another difficulty raised in the polymerization of isocyanates is solubility to a solvent.
Since the solubility of a monomer and a polymer obtained at low temperature to dimethylformamide (DMF), a commonly used solvent, is not good, the molecular weight distribution becomes broader and the yield decreases.
As a result, the yield was improved, but there was no noticeable improvement in the molecular weight distribution.
In this case, however, it was observed that the formation of dimers and trimers became more serious.
However, there were still some drawbacks in that the yield was as low as 32% to 70%, and the molecular weight distribution was as uncontrollable as 2 to 4.
In this case, however, there were also some drawbacks in that a catalyst system, which was very complex and expensive, should be used for the coordination polymerization, the yield was still lower than 100%, and copolymerization with other monomers was not possible.
However, they did not take into considerations of various parameters for living conditions and for structure-control, such as reaction time, counter ion, and the like.
However, it has a difficulty in the process due to the use of an additive.
However, it has some drawbacks such as long reaction time and low initiation efficiency due to a low reactivity of the amidate anion.
As described above, according to the conventional methods for preparing polyisocyanates, it is difficult to control the molecular weight due to the formation of dimers or trimers, and they have some drawbacks such as a difficulty in the process due to the use of an additive, deterioration of reaction yield due to the low reactivity, and a broad molecular weight distribution.

Method used

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  • Metal carbonate initiator and method for polymerizing isocyanates using the same
  • Metal carbonate initiator and method for polymerizing isocyanates using the same
  • Metal carbonate initiator and method for polymerizing isocyanates using the same

Examples

Experimental program
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Effect test

example 1

[0054]Poly(n-hexylisocyanate) was prepared using n-hexylisocyanate (HIC) shown in Table 1 in the following manner. The reaction conditions were −98° C. and 10−6 torr, and the reaction time was set to 5 to 15 minutes. To set the reaction temperature, liquid nitrogen was added to methanol contained in a constant temperature bath to freeze the methanol, and the temperature was measured using a low-temperature thermometer. Pale yellow sodium-deoxybenzoin (Na—DB) obtained by reacting sodium metal with an equivalent amount of deoxybenzoin in a tetrahydrofuran (THF) solvent was used as the initiator. The thus prepared initiator was immediately put into a glass ampoule under vacuum and then diluted to an appropriate concentration. A polymerization unit shown in FIG. 1, comprising the glass ampoule containing purified n-hexylisocyanate, i.e., an isocyanate monomer, the initiator prepared in the above-described manner, and a reaction terminator, was connected to a vacuum line to be in a high ...

example 2

[0057]Poly(n-hexylisocyanate) was prepared in the same manner as Example 1, except that the reaction molar ratio was differentiated as shown in the following Table 2 to examine the effects according to the change of the molecular weight during the polymerization. At this time, the reaction time was set to 10 minutes, which was the optimum reaction condition.

[0058]

TABLE 2PolymerizationNumber-average molecularPolydispersitycomponent (mmol)weight (Mn)indexYieldClassificationNa-DB a)HIC b)Calculated c)Measured d)(Mw / Mn)(%)Example 2-10.2728.644240115001.08100Example 2-20.25312.36330191001.0399Example 2-30.27017.88390245001.0598Example 2-40.23122.412300353001.0798a) Initiator: sodium-deoxybenzoinb) Isocyanate monomer: n-hexylisocyanatec) Calculated value: {(monomer content / initiator content) × molecular weight of hexylisocyanate (127.19) + molecular weight of deoxybenzoin (196.25)} × polymer yield / 100d) Measured value: measured at 40° C. using gel permeation chromatography (GPC) and light...

example 3

[0059]Poly(3-(triethoxysilyl)propyl isocyanate) was prepared in the same manner as Example 1, except that 3-(triethoxysilyl)propyl isocyanate (TESPI) was used. At this time, the reaction time was set to 5 to 12 minutes, and the reaction was terminated by methanol. The thus prepared polymer was precipitated in excess methanol and then vacuum-dried.

[0060]

TABLE 3PolymerizationReactionNumber-average molecularPolydispersitycomponent (mmol)timeweight (Mn)indexYieldClassificationNa-DB a)TESPI b)(min)Calculated c)Measured d)(Mw / Mn)(%)Example 3-10.2423.8352840104001.1369 (31) e)Example 3-20.2423.8383990107001.1197Example 3-30.2443.97103800113001.1190 (10) f)Example 3-40.2453.69123140107001.1280 (20) f)a) Initiator: sodium-deoxybenzoinb) Isocyanate monomer: 3-(triethoxysilyl)propyl isocyanatec) Calculated value: {(monomer content / initiator content) × molecular weight of 3-(triethoxysilyl)propyl isocyanate (247.37) + molecular weight of deoxybenzoin (196.25)} × polymer yield / 100d) Measured val...

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Abstract

Disclosed herein is a metal enolate initiator for polymerizing isocyanates and a method for polymerizing isocyanates by anionic polymerization using the same, in which the initiator forms a cluster upon the initiation and protects stability of terminal anions at the end of the chain to cause controlled polymerization, thus preventing depolymerizaton and improving reaction time and efficiency without the use of a separate additive.

Description

CROSS-REFERENCE TO RELATED APPLICATION[0001]This application claims the benefit of Korean Patent Application No. 10-2006-0069998, filed on 25 July, 2006, the entire disclosure of which is hereby incorporated by reference.BACKGROUND OF THE INVENTION[0002]1. Field of the Invention[0003]The present invention relates to an initiator for polymerizing isocyanates, more particularly, to a metal enolate initiator for polymerizing isocyanates and a method for polymerizing isocyanates by anionic polymerization using the same, in which the initiator forms a cluster upon the initiation and protects stability of terminal anions at the end of the chain to cause controlled polymerization, thus preventing depolymerizaton and improving reaction time and efficiency without the use of a separate additive.[0004]2. Description of Related Art[0005]In general, polyisocyanates are prepared by anionic polymerization [Bur, A. J.; Fetters, L. J. Chem. Rev. 1976, 76, 727.]. Typically, the anionic polymerizatio...

Claims

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Application Information

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Patent Type & Authority Patents(United States)
IPC IPC(8): C08G18/22C07C65/32
CPCC08G18/02C08G18/16C08G18/00C08F4/08
Inventor LEE, JAE-SUKYOO, HEE-SOORAHMAN, SHAHINUR
Owner GWANGJU INST OF SCI & TECH
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